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Improved electrospray ionization interface for capillary zone electrophoresis-mass spectrometry

Journal Article · · Anal. Chem.; (United States)
DOI:https://doi.org/10.1021/ac00169a022· OSTI ID:6723720

A new electrospray ionization interface for capillary zone electrophoresis-mass spectrometry (CZE-MS) is described. The interface uses a sheath flow of liquid to make the electrical contact at the CZE terminus, thus defining both the CZE and electrospray field gradients. This allows the composition of the electrosprayed liquid to be controlled independently of the CZE buffer, providing operation with buffers that could not be used previously (e.g., aqueous and high ionic strength buffers). The interface operation is independent of CZE flow rate; CZE capillaries are easily replaced and require no additional preparation. Since the electrospray occurs directly from the CZE capillary terminus, additional mixing volumes and metal surfaces are avoided and electrophoretic separation efficiency appears unperturbed. The dead volume associated with the electrospray interface is < 10 nL, corresponding to < 0.1 s for typical flow rates of the sheath electrode liquid. CZE-MS separations for mixtures of quaternary phosphonium salts and for epinephrine and related amines are demonstrated. Operation is demonstrated with high surfactant concentrations, as required for capillary electrokinetic chromatography. The extension to other capillary electrophoresis methods, such as isotachophoresis and isoelectric focusing, appears feasible.

Research Organization:
Pacific Northwest Lab., Richland, WA (USA)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
6723720
Journal Information:
Anal. Chem.; (United States), Journal Name: Anal. Chem.; (United States) Vol. 60:18; ISSN ANCHA
Country of Publication:
United States
Language:
English